// 提供各种混合样式

// 定位居中
.self-center(@position: absolute) {
  position: @position;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
// 弹性居中
.self-center-flex {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}
// 自填充
.self-fill(@position: absolute) {
  position: @position;
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
}